I just had a really good mechanic come over and feel things out and what concerned him the most was a sound coming from around the throttle body. It was a hiss. After I would crank it over a few times you could here it hiss like pressure was being equalized or something. He said it sounded rather strange and we still couldn't get it to start. I checked the cam sensor and it seems OK. I am at a total loss and frustrated. Maybe time to throw in the towel. Sucks.

 

Changed the plugs out and I can hear it sputtering more than before but it just won't start. One of the plug wire boots was loose and i fixed that. My mechanic friend seems to think it may be something with the EGR valve. I'm gonna put some new injectors and a new coil in it on the next go round. All the sensors have tested good. It seems like it's something simple that's being overlooked.

 

The chassis has been taken such good care of it's practically perfect. If we don't get locked down into oblivion, and work stays plentiful, I would seriously consider buying another 4.0 and getting it put in if I had to. Something about that beast that looks so worth saving. The only time it actually started was immediately after the new fuel pump. It started instantly, too, but died after about 5 seconds. That's the only time it did that and I wish I knew why.

 

I wouldn't think it's an engine problem. Probably some simple sensor somewhere like you said. Forgive me if I missed it, but do you have fuel pressure at the rail?

 

Okay. Major breakthrough. I just replaced the fuel pump and the filter. The pump primes when I turn the key just fine, but I just noticed it isn't holding pressure at the rail as evidenced by me just now priming it then relieving the shrader valve to a small squirt then a drip. I took out the injectors and cleaned them a couple of months ago and I'm thinking maybe the o-rings should have been replaced at that time. Just got a set of o-rings and I'm gonna take the whole fuel rail off and put the new o-rings on. Number 2 (from the front) injector is leaky. This could be the whole problem. Please forgive me for being a novice mechanic, but if this isn't the WHOLE problem its gotta be at least A problem. Since the o-rings, I found out, should be replaced any time the injectors are removed I'm gonna put the new o-rings in and check again after I put the rail and injectors back in. I've also heard of fuel pump check valves being bad from the factory on non-OEM autozone parts, so if I get the injectors sealed nice and tight like they are supposed to be, I can troubleshoot further. No pressure is the problem, or at least A MAJOR problem. Sorry I missed something so obvious, and I really appreciate you cats giving me advice on this. Maybe I'm not as screwed as I thought.

 

Does it prime again when you crank the engine? If not, then I'd suspect the crank sensor.

 

The best advice I can give you is to take your time. This is a marathon, not a sprint. You will probably have to go through everything with a fine tooth comb. Suspect that everything could be bad until you test it. You replaced the plugs, did you replace or at least check the wires?

You say that you have good spark, and you say that it started when you put the new fuel pump in, but then it died. It seems that from what you say, the fuel pump is not holding pressure. Do you have, or can you rent at a parts store, a fuel pressure gauge. You can get an actual number of the pressure it is holding, I believe the number is 39-45 psi, but you will have to double check that. The pump may be able to build up a little pressure, but when trying to run it can't provide the volume.

I am by no means an expert, but I just try to offer advice.

 

Ok I skimmed over your post again and I have a few things you can look at, forgive me if you looked at these already. One if you have a bad vaccum leak (injector o rings, intake manifold gasket or TB gasket) that will make the MAP sensor think the engine needs a lot more fuel then it should need. Two if the fuel pressure regulator is bad not hold pressure which would not give the injectors the fuel they need or leaking fuel into the vaccum line to the intake manifold which would give you to much fuel. Three after cranking over the motor with a no start check to see if the spark plugs a wet meaning way to much fuel. Hope that helps good luck.

 

Thanks guys. Got the new injector o-ring kit in and the rail back on. It seems like maybe they aren't seated well on the intake side, but it got dark on me, so I'm gonna check it out tomorrow and let you guys know. I can see the back of the o-rings on the intake side of the injector. Need to try to work them in a little better tomorrow, and then check pressure. Got a feeling after I cleaned them a few months ago I may have never really had them fully seated this whole time. I'm having fun and learning a lot at least. Can't wait to see her run again. I have taken off and cleaned the throttle body recently and put a new gasket and some sealant and it should be fine. That little IAC thingy could possibly be sticking but it takes a special tool to check it. I cleaned it up and put it back when I did the throttle body. Those little metal retaining clips are giving me hell getting them back on the injectors and I lost one of them.

 

AHA! Put new o-rings in and still wasn't getting pressure so I decided to short the fuel pump relay so I could see the action (or lack thereof). 3rd injector from the front was leaking like a sieve. This is AFTER putting on new o-rings. Maybe a new set is in order? Also, my connection to the fuel filter was dripping a little bit and I took it loose and redid the fittings and it stopped. All my fuel pressure seems to be escaping through the injectors. I sincerely believe once this problem is solved she's gonna run again. The temptation to buy cheap Chinese injectors is overwhelming. i may be able to swing a set from a friend with a dead 89. Same one I recovered the 'new' PCM from. The plot thickens...

 

You might have damaged the o-ring putting it in. The oem injectors from an 89 had metal bodies, and mine started weeping through the rust. There are a few guys who sell refurbished Bosch injectors. I got a set of Bosch 746 injectors from jhc7399 for a good price a while back that worked great. You might try PMing him. Avoid the cheap chinese knock-offs. There have been lots of posts about them being bad and not matched for flow rates.

 

I found a set of refurbished bosh's for 80 bones on ebay. Hey. Quick question: If I remove the line from the regulator and plug it with my thumb get my buddy to turn the ignition and prime the rail and i still lose pressure instantly, will that rule out the regulator and let me know for sure the injectors are my problem? Anyway, pinpointing the pressure leak is what I really need to do. I've never dug this deep into a vehicle before but it is fascinating methinks.

 

I wouldn't try plugging it with your thumb. Just gonna spray yourself with gas.

Put a real pressure gauge no there and see what it's doing. A little squirt after just priming is normal. See if you get it a few minutes after turning the key off.

 

Try taking the vac line off the injector. Make sure it's not leaking gas into the vac line.

 

Thanks guys. I just got a sick deal on a set of Bosch injectors on eBay. Supposedly new. Gonna stop by harbor freight and buy a pressure gauge, too. So excited about possibly being running soon, but then I realized I haven't even dealt with the tranny yet. Yikes. Guess I'll cross that bridge soon. Also, to the gentleman asking about gas in the vac line, I checked it and there wasn't any.